1. Field of the Invention
The present invention relates to a tool for a hand-held equipment and including a shank having, in its clamping region, at least one looking groove and at least one drive groove which opens toward the rear end of the shank.
2. Description of the Prior Art
The prior art discloses a number of tools the shanks of which are specifically adapted for insertion in a chuck of a hand-held equipment. Such tools are disclosed, e.g., in European Publications EP-A-0 433 876, EP-B-0 550 489, EP-A-0 584 706 and German Publications DE-A-43 03 545 and DE-U-093 19 009. The tools described in these publications differ from each other by the arrangement and shape of the drive grooves provided on the tool shank or of the driving elements provided in the chuck of the hand-held equipment. In addition to drive grooves, locking grooves are provided on the shank which, in distinction from the drive grooves, are generally axially closed. The locking grooves should prevent a tool from out of the chuck of the hand-held equipment. They also contribute to the torque transmission.
An object of the present invention is a tool for hand-held equipment and having drive grooves and locking grooves the shape and dimensions of which are so selected that the torque transmission and retaining of the tool in the chuck are optimized.
Another object of the present invention is a tool having a sufficiently large, non-weakened remnant cross-section of the shank which is adequate for an optimal transmission of a large energy of a single blow of modern percussion hand-held equipments, and which has an adequate fracture resistance.